Solution:2

Solution:3

I think, based on your mention of Visual C# Express, that what you're looking for is an IDE (integrated development environment), not a compiler as such. Go to http://java.sun.com/javase/downloads/ and get the NetBeans bundle.

Solution:5

Since the Java language and platform are fully specified, there are various other implementations of the Java environment; for example, both Oracle and IBM sell products which incorporate their own Java Runtime Environments, etc.

You mentioned "C# Express" in your question, by which I assume you meant the version of Visual Studio Express that supports C#; Visual Studio is an integrated development environment, which provides source code editing, refactoring, and debugging facilities, and interacts with the compiler and build processes on your behalf. If you're looking for an IDE for Java, then you might want to take a look at NetBeans (which is sponsored by Sun) or Eclipse.

Solution:6

Solution:7

Solution:8

If you don not require an IDE then you can download the standalone JDK.

Solution:9

There is no official compiler in Java as such. Java is a set of specification driven by community. You can call it just a piece of document. What sun does is that it provides a reference implementation to this document. You can download from the links as given above. You can install Java as mentioned in http://oyejava.com/tiki-index.php?page=Installing+Java